Fix log10 expected test result
Fix log10 expected test result

The result was off by 1ulp. This was confirmed using bc
with much higher precision.

Signed-off-by: Paul E. Murphy <bcb79dc2d3103f301c432ff2685f8b89fad82826@linux.vnet.ibm.com>

pmur/libdfp,pmur/libdfp,pmur/libdfp,pmur/libdfp,gftg85/libdfp,gftg85/libdfp,gftg85/libdfp,gftg85/libdfp